1. Field
The embodiments relate to composite material, and more specifically to a method and apparatus for producing off-axis composite prepreg material for fabricating composite parts for aircraft.
2. Background
Known methods and apparatuses exist for producing multi-ply tape and fabricating cross-plied structural material. Such known methods include using many layers of carbon tape with standard ply angle fiber orientations, such as 0 degree, plus and minus 45 degree, and 90 degree. Newer investigations indicate that there may be very significant weight savings using nonstandard ply angle fiber orientation, such as plus and minus 5 degree, and plus and minus 65 degree ply angle orientations for aircraft composite parts. The 65 degree ply angle orientations can easily be laid down with existing equipment. However, the plus and minus 5 degree ply angle orientation causes difficulty for current lay-up processes, especially for narrow aircraft composite parts, such as stringer lay-ups. Making very shallow angle cuts in prepreg tape is impractical or impossible with all current prepreg laminating machines. It is possible to avoid shallow angle cuts by running the courses off the edge of the part, but this causes large amounts of material to be wasted. Currently, to gain the weight benefit of these shallow angle lay-ups, manual cutting and lay-up is required. Even with manual cutting, this can be difficult because of the length of the cuts (i.e., about 69 inches long for a 6 inch wide tape) and the long wispy tails that result that are hard to manage. The preferred approach is to obtain a roll of prepreg material that is already arranged in one layer of plus 5 degree tape and a second layer of minus 5 degree tape. However, such a product configuration is not known or available.
There is research that indicates that use of nonstandard ply angle orientations can result in significant weight savings. But the implementation methods are limited. Hand lay-up is expensive, and lay-up with existing machines causes significant material waste, especially for narrow parts. If the plus and minus 5 degree material is efficiently produced, it can be laid down with conventional tape laying machines. In fact, it can increase productivity because two layers may be laid down at once.
Accordingly, there is a need for an improved method and apparatus for producing off-axis composite prepreg material that does not have the problems associated with known methods and devices.